Daniel 9:1

In the first year of Darius the son of Ahasuerus, of Median descent, who was made king over the realm of the Chaldeans—

Daniel 11:1

“Also I, in the first year of Darius the Mede, I (Gabriel) arose to be an encouragement and a protection for him.

Daniel 1:21

And Daniel remained there until the first year of [the reign of] King Cyrus [over Babylon; now this was at the end of the seventy-year exile of Judah (the Southern Kingdom) in Babylonia, as foretold by Jeremiah].

Daniel 5:31-1

So Darius the Mede received the kingdom; he was about the age of sixty-two.

Daniel 6:28

So this [man] Daniel prospered and enjoyed success in the reign of Darius and in the reign of Cyrus the Persian.

Treasury of Scripture Knowledge

Summary

In the first year of Darius the son of Ahasuerus, of the seed of the Medes, which was made king over the realm of the Chaldeans;

Bible References

Darius

Daniel 1:21
And Daniel remained there until the first year of [the reign of] King Cyrus [over Babylon; now this was at the end of the seventy-year exile of Judah (the Southern Kingdom) in Babylonia, as foretold by Jeremiah].
Daniel 5:31
So Darius the Mede received the kingdom; he was about the age of sixty-two.
Daniel 6:1
It seemed good to Darius [who became king after Belshazzar] to appoint over the kingdom 120 satraps who would be in charge throughout the kingdom,
Daniel 11:1
“Also I, in the first year of Darius the Mede, I (Gabriel) arose to be an encouragement and a protection for him.